Imaging apparatus and imaging method

ABSTRACT

An apparatus suitably detects a recording trigger even in a low-brightness or low-light-intensity environment, and acquires, from a recorded image, a high-quality image from which a person or the like can be easily recognized. When a recording trigger is to be detected, this apparatus disables an infrared reduction filter, so a recording trigger can be suitably detected even in an environment in which the brightness or light intensity is low. When an image is to be recorded, this apparatus records a color image by enabling the infrared reduction filter.

This application is a continuation of application Ser. No. 11/460,419filed Jul. 27, 2006.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a technique for automatically recording imagessuch as still images and moving images.

2. Description of the Related Art

A security system for automatically recording images such as stillimages and moving images by a security camera and recording the imageson a recording medium is conventionally known. Although the quality ofthe recorded image is desirably as high as possible, it is alsodesirable to increase the recording time as long as possible. However,there is a tradeoff relationship between the image quality and recordingtime, so it is generally difficult to achieve high image quality andlong-term recording simultaneously.

Accordingly, a security system which performs recording at highresolution in scenes regarded as important and performs recording at lowresolution in scenes not regarded as important is proposed (JapanesePatent Laid-Open No. 2002-016877). This security system determines theimportance of a scene on the basis of the motion of an object.

To perform monitoring for a longer period of time, it is only necessaryto record no images in (normal) scenes with no motion, and record imagesin (abnormal) scenes with motion. This makes it possible to preserve therecording medium.

In a security system which records an image only when an abnormality isdetected, however, no images are recorded in normal scenes, so nothingmay be recorded if the detection of an abnormality has failed.

A monitoring environment in which the detection of an abnormality easilyfails is principally an environment in which the brightness or lightintensity is low. Especially when the number of image pickup elements ofan imaging device is increased to increase the resolution, the effectivelight receiver area per image pickup element is normally reduced. Sincethe sensitivity lowers accordingly, the possibility of an abnormalitydetection failure increases more and more.

SUMMARY OF THE INVENTION

The present invention makes it possible to suitably detect a recordingtrigger even in a low-brightness or low-light-intensity environment bydisabling an infrared reduction filter. When recording is to beperformed, on the other hand, a color image is recorded by enabling theinfrared reduction filter. Accordingly, a person or the like can bereadily recognized from a recorded image.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments (with reference to theattached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a block diagram showing an example of the arrangement of animaging apparatus according to an embodiment;

FIG. 2A is a view for explaining the relationship between an infraredreduction filter according to the embodiment and an imaging device whenthe filter is placed in a light path;

FIG. 2B is a view for explaining the imaging device when the infraredreduction filter according to the embodiment is moved away from thelight path;

FIG. 3 is a flowchart illustrating an imaging method according to theembodiment;

FIG. 4 is a flowchart illustrating another still image sensing methodaccording to the embodiment;

FIG. 5A is a view for explaining the relationship between an infraredreduction filter according to another embodiment and an imaging devicewhen the filter is placed in a light path;

FIG. 5B is a view for explaining the imaging device when the infraredreduction filter according to the embodiment in FIG. 5A is moved awayfrom the light path; and

FIG. 6 is a flowchart illustrating a moving image recording methodaccording to the embodiment in FIGS. 5A and 5B.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

First Embodiment

FIG. 1 is a block diagram showing an example of the arrangement of animaging apparatus according to an embodiment. This imaging apparatus (tobe referred to as a camera hereinafter) is a so-called security camera,video camera, or digital still camera. The camera may also be, e.g., acamera which records images such as moving images and still images, andtransmits the images outside via a network. Other examples of the cameraare a camera which outputs video signals outside, and a camera whichrecords images on a recording medium (e.g., a tape, semiconductormemory, optical disk, or magnetic disk).

Referring to FIG. 1, the individual units in the camera are connectedvia a bus 159, and comprehensively controlled by a main CPU 151. A lensunit 101 includes, e.g., a fixed lens 102, zoom lens 103, aperture stop,fixed lens 104, and focusing lens 105. An object is imaged by forming anoptical image of the object on an imaging device 141 through theseoptical members. A zoom control unit 125 drives the zoom lens 103 via azoom motor 121 in accordance with instructions from the main CPU 151.

An infrared reduction filter 106 is an optical filter which reduces orintercepts light components in the infrared band. The infrared reductionfilter 106 is driven by a driving motor 123, and placed in or moved awayfrom a light path of the lens unit 101. The driving motor 123 iscontrolled by an infrared reduction control unit 126. The driving motor123 and infrared reduction control unit 126 are exemplary means formoving the infrared reduction filter 106. Note that when the infraredreduction filter 106 is placed in the light path, the object imageformed on the imaging device 141 contains no light in the infrared band.When the infrared reduction filter 106 is moved away from the lightpath, the object image formed on the imaging device 141 contains lightin the infrared band.

A lighting device 124 emits light or is lit in synchronism with therecording timing in accordance with instructions from the CPU 151. Sincean object is illuminated by this light, an image of the object can beclearly recorded even when the brightness is low. An example of thelighting device for still image recording is a flash light unit whichinstantaneously emits light. An example of the lighting device formoving image recording is a video light unit capable of continuouslighting.

The image formed on the imaging device 141 is photoelectricallytransduced, and input as an image signal to an imaging signal processingunit 142. A CCD sensor or CMOS sensor can be used as the imaging device141. The imaging signal processing unit 142 performs A/D conversion andother image processing on the input image signal. After that, the imagesignal is input to a focal point detection unit 131.

An imaging control unit 143 sets the imaging resolution, image signalread method, frame rate, and the like of the imaging device 141. Theimage signal read method is, e.g., addition read or all image pickupelements read (to be described later). The imaging signal processingunit 142 also executes signal processing matching various conditionssuch as the resolution and frame rate designated by the imaging controlunit 143, and disable/enable of the infrared reduction filter 106.

A motion detection unit 152 is an example of a unit which detects achange relating to an object. Another detection unit may also be used aslong as the unit can suitably detect a recording trigger. The motiondetection unit 152 stores several images processed by the imaging signalprocessing unit 142 into a RAM 154 in the order of recording. The motiondetection unit 152 determines whether there is a motion by correlating aplurality of images.

The focal point detection unit 131 includes at least one distancemeasurement gate 132, at least one bandpass filter (BPF) 133, and atleast one wave detector 134. The distance measurement gate 132 extractsa partial image signal forming an image. The bandpass filter (BPF) 133extracts a predetermined hi-frequency component contained in the imagesignal. This hi-frequency component is a frequency component effectiveto determine an evaluated value of autofocusing. The cutoff frequency ofthe BPF 133 is experimentally determined. The wave detector 134 performsa wave detection process such as peak holding or integration, andoutputs an AF evaluated value S1. The AF evaluated value S1 is input toa focus control unit 135. Note that if a plurality of distancemeasurement gates 132, a plurality of BPFs 133, and a plurality of wavedetectors 134 exist, a plurality of signals are output as AF evaluatedvalues S1 accordingly. The focus control unit 135 executes autofocusingcontrol on some or all of the evaluated values S1. On the basis of theAF evaluated value S1, the focus control unit 135 detects a position(focused focal point) at which the AF evaluated value S1 is at amaximum. The focus control unit 135 then drives the focusing motor 122to move the focusing lens 105 to the focused focal point. In thismanner, autofocusing (AF) is realized.

The image signal processed by the imaging signal processing unit 142 istemporarily stored as image data in the RAM 154. The image data storedin the RAM 154 is compressed by an image compressing/decompressing unit153. The CPU 151 may record the compressed image data on a recordingmedium 156. The CPU 151 may also transmit the compressed image dataoutside as a network signal S3 via a network interface 157. The CPU 151may also output the image data as a video signal S2 from a video outputunit 158 to a TV monitor or PC monitor in parallel with the recordingprocess.

Note that when the camera is activated, a control program stored in aflash memory 155 is loaded into a portion of the RAM 154. The CPU 151controls the individual units as described above in accordance with theprogram loaded into the RAM 154.

FIG. 2A is a view for explaining the relationship between the infraredreduction filter according to the embodiment and the imaging device whenthe filter is placed on the light path. Reference numeral 201 representsthe whole effective region of the imaging device to which primary colorfilters are adhered. In a normal recording operation, the wholeeffective region is an imaging region for acquiring an image. However,when special recording such as electronic camera shake prevention is tobe performed, a portion of the whole effective region is sometimes usedas an imaging region. Each square in FIG. 2A indicates one photoelectrictransducer. Reference numeral 202 denotes a partial region of theimaging device; 211, a photoelectric transducer to which a red filter isadhered; 212 and 213, photoelectric transducers to which green filtersare adhered; and 214, a photoelectric transducer to which a blue filteris adhered. The imaging signal processing unit 142 reads out an imagesignal from each photoelectric transducer, and forms a high-resolutioncolor image on the basis of the relationship between the photoelectrictransducer and primary color filter.

FIG. 2B is a view for explaining the imaging device when the infraredreduction filter according to the embodiment is moved away from thelight path. Like reference numeral 202, reference numeral 204 denotesthe whole effective region of the imaging device. Reference numeral 205denotes a partial region of the imaging device. FIG. 2B particularlyshows that signals from the four photoelectric transducers 211, 212,213, and 214 are added and read out as a signal of R+B+2G. Referencenumeral 221 denotes a photoelectric transducer group including the fourphotoelectric transducers 211, 212, 213, and 214. As shown in FIG. 2B,the light receiver area of the photoelectric transducer group is fourtimes that of one photoelectric transducer. This means that thesensitivity increases.

When the infrared reduction filter 106 is not placed in the light path,all light components in the infrared band are transmitted. Accordingly,no clear color separation can be realized by the R, G, and B filters.Also, when signals from the four photoelectric transducers are added andread out, pieces of color information cancel each other out, so only abrightness signal can be obtained. However, there is also the advantagethat an image signal having fourfold sensitivity can be obtained.Therefore, the imaging signal processing unit 142 forms ahigh-sensitivity, monochrome image by using the image signal obtained atthe fourfold sensitivity. Note that in the state shown in FIG. 2B, thenumber of image signals to be read out is reduced to ¼. As a result, theframe rate is easily increased.

FIG. 3 is a flowchart illustrating an imaging method according to theembodiment. In step S301, the CPU 151 instructs the infrared reductioncontrol unit 126 to drive the driving motor 123. This is an instructionto move the infrared reduction filter 106 away from the light path. Inresponse to this instruction, the infrared reduction control unit 126drives the driving motor 123, thereby moving the infrared reductionfilter 106 away from the light path.

In step S302, the CPU 151 transmits an imaging instruction to theimaging control unit 143. In response to this instruction, the imagingcontrol unit 143 reads out an image signal from the imaging device 141,and outputs the readout image signal to the imaging signal processingunit 142. Note that image data is formed from the image signal andwritten in the RAM 154.

In step S303, the CPU 151 determines whether the object has changed.More specifically, the CPU 151 detects the motion of the object bycomparing a plurality of images by using the motion detection unit 152.If the object has not changed, the flow returns to step S302. If theobject has changed, the flow advances to step S304.

In step S304, the CPU 151 drives the driving motor 123 via the infraredreduction control unit 126, thereby placing the infrared reductionfilter 106 in the light path.

In step S305, the CPU 151 records a color image on the basis of theimage signal acquired by the imaging device 141. This color image may berecorded on the recording medium 156, or transmitted to a predeterminedPC via the network interface 157.

In step S306, the CPU 151 determines whether to terminate monitoring. Ifmonitoring is to be continued, the flow returns to step S301; if not,the CPU 151 terminates the recording process.

In this embodiment, a recording trigger can be suitably detected even ina low-brightness or low-light-intensity environment by disabling theinfrared reduction filter. When recording is to be performed, on theother hand, a color image is recorded by enabling the infrared reductionfilter. Accordingly, a person or the like can be readily recognized froma recorded image.

FIG. 4 is a flowchart illustrating another still image sensing methodaccording to the embodiment. Note that this imaging method is the lowerconcept of the imaging method shown in FIG. 3. In step S401, the CPU 151measures the brightness of an object from an image signal read out fromthe imaging device 141.

In step S402, the CPU 151 determines whether the object brightness islow. For example, the CPU 151 compares the brightness of the object witha predetermined threshold value to determine whether the brightness islow. The threshold value is empirically determined. If the brightness islow, the flow advances to step S403; if not, the flow advances to stepS404, and the CPU 151 performs control such that the infrared reductionfilter 106 is placed in the light path. In step S403, the CPU 151performs control such that the infrared filter 106 moves away from thelight path.

In step S405, the CPU 151 adds and reads out image signals from eachgroup of four photoelectric transducers of all photoelectric transducersforming the imaging device 141. The signal addition unit may also beincorporated into the imaging device 141. In this case, whether to readout an image signal from each photoelectric transducer or read out anadded image signal can be switched by a control signal from the CPU 151.Also, the CPU 151 sets the imaging signal processing unit 142 so as toread out image signals at a frame rate higher than a normal frame rate.The normal frame rate is a frame rate for recording color images, and isa relatively low frame rate. In step S406, the CPU 151 controls theimaging signal processing unit 142 to sense a monochrome image at highsensitivity.

In step S407, the CPU 151 causes the motion detection unit 152 toexecute motion detection by using the image signal acquired at highsensitivity. If no motion is detected, the flow returns to step S401. Ifa motion is detected, the flow advances to step S409.

In step S409, the CPU 151 causes the focus control unit 135 to detect afocused focal point. In step S410, the CPU 151 corrects the focusedfocal point for infrared recording and visible light recording.

In step S420, the CPU 151 places the infrared reduction filter 106 inthe light path in order to perform color imaging. In step S421, the CPU151 sets the imaging device 141 so as to read out image signals from allthe photoelectric transducers. Consequently, as shown in FIG. 2A, imagesignals for forming a color image can be acquired.

In step S422, the CPU 151 measures the brightness of the object from theimage signals. In step S423, the CPU 151 determines whether thebrightness of the object is low. If the brightness is not low, the flowadvances to step S425. If the brightness is low, the flow advances tostep S424, and the CPU 151 turns on the flash light as a lighting device124. The flash light of course emits light in synchronism withrecording.

In step S425, the CPU 151 records a high-resolution color still image.In step S426, the CPU 151 temporarily stores image data of the recordedcolor still image in the RAM 154. In step S427, the CPU 151 reads outthe image data from the RAM 154, and transmits the image data outsidevia the network interface 157. After that, the flow returns to stepS401. Note that it is also possible to record the image data on therecording medium 156, instead of distributing it to the network. It isof course also possible to display the image on the monitor via thevideo output unit 158.

In this embodiment as explained above, when a change relating to anobject is to be detected, the infrared reduction filter 106 is disabled.Accordingly, a change can be suitably detected even in a low-brightnessor low-light-intensity environment. When recording is to be performed,on the other hand, a color image is recorded by enabling the infraredreduction filter 106. Therefore, a person or the like is readilyrecognizable from the recorded image.

Especially when a change relating to an object is to be detected in thisembodiment, image signals output from each group of four photoelectrictransducers forming the imaging device 141 are added and read out as animage signal of one image pickup element. Accordingly, the actualsensitivity can be increased. Also, the frame rate can be easilyincreased because image signals smaller in number than all the pixelsforming the imaging device 141 are output. That is, imaging can beexecuted at a frame rate higher than the frame rate at which imaging isperformed by using all the photoelectric transducers forming the imagingdevice 141. This is because the data transfer rate need not be high ifthe number of image pickup elements is reduced. When the frame raterises, the operating speed of AF can also be increased. Note that fourphotoelectric transducers are grouped into one unit in the aboveembodiment, but it is needless to say that the number of photoelectrictransducers need only be two or more.

Also, in the above embodiment, the number of image pickup elements isreduced by adding image signals from a plurality of photoelectrictransducers. However, it is also possible to read out image signals fromonly some of a plurality of photoelectric transducers. This makes itpossible to increase both the frame rate and AF operating speed.

Note that when a color image is to be recorded, the number of imagepickup elements is larger than that when a change relating to an objectis to be detected, so a high-resolution color image can be acquired.This is advantageous to specify a person or the like. Note also thatwhen a high-resolution color image is to be acquired, the imaging device141 is set at a relatively low frame rate. This can solve the problem ofthe data transfer rate as well.

It is also possible to extract a hi-frequency component of an outputimage signal from the imaging device 141 by the BPF, thereby detectingthe focused focal point of the imaging optical system. This is becausewhen a hi-frequency component is used, the focused focal point can beeasily detected even in a low-brightness environment.

Furthermore, the lighting device 124 may also execute lighting only whenan image is to be recorded, without performing any lighting when achange relating to an object is to be detected. As a consequence, theelectric power consumed by the lighting device 124 can be saved. Notethat when the camera includes the network interface 157 which transmitsrecorded color images outside, image data can be erased from the RAM154, so long-time recording can be readily achieved. Long-time recordingcan also be easily realized by transferring image data to the removablerecording medium 156.

Second Embodiment

In the second embodiment, an example of moving image recording will beexplained. FIG. 5A is a view for explaining the relationship between aninfrared reduction filter according to the embodiment and an imagingdevice when the filter is placed in a light path. Reference numeral 501denotes the whole effective region of an imaging device 141 to whichcomplementary color filters are adhered. Each square in FIG. 5Aindicates one photoelectric transducer. Reference numeral 502 denotes apartial region of the imaging device 141; 511, a photoelectrictransducer to which a cyan filter is adhered; 512, a photoelectrictransducer to which a green filter is adhered; 513, a photoelectrictransducer to which a yellow filter is adhered; and 514, a photoelectrictransducer to which a magenta filter is adhered. An imaging signalprocessing unit 142 reads out an image signal from each photoelectrictransducer, and forms a high-resolution color image on the basis of therelationship between the photoelectric transducer and complementarycolor filter.

FIG. 5B is a view for explaining the imaging device when the infraredreduction filter according to the embodiment is moved away from thelight path. Like reference numeral 502, reference numeral 504 denotesthe whole effective region of the imaging device 141. Reference numeral505 denotes a partial region of the imaging device 141. FIG. 5Bparticularly shows that signals from the four photoelectric transducers511, 512, 513, and 514 are added and read out as a signal of Cy+Ye+Mg+G.Reference numeral 521 denotes a photoelectric transducer group includingthe four photoelectric transducers 511, 512, 513, and 514. As can beapparent from FIG. 5B, the light receiver area of the photoelectrictransducer group is four times that of one photoelectric transducer.This means that the sensitivity increases.

When an infrared reduction filter 106 is not placed in the light path,all light components in the infrared band are transmitted, so colorscannot be clearly separated by the Cy, Ye, Mg, and G filters. Also, whensignals from the four photoelectric transducers are added and read out,only a brightness signal can be obtained. This is because pieces ofcolor information cancel each other out by the addition. However, thereis the advantage that an image signal having fourfold sensitivity can beobtained. Therefore, the imaging signal processing unit 142 forms ahigh-sensitivity, monochrome image by using the image signal obtained atfourfold sensitivity. Note that in the state shown in FIG. 5B, thenumber of image signals to be read out reduces to ¼, resulting in theadvantage that the frame rate is easily increased.

FIG. 6 is a flowchart illustrating a moving image recording methodaccording to the embodiment. Note that this imaging method is the lowerconcept of the imaging method shown in FIG. 3. In step S601, a CPU 151measures the brightness of an object from an image signal read out fromthe imaging device 141.

In step S602, the CPU 151 determines whether the object brightness islow. For example, the CPU 151 compares the brightness of the object witha predetermined threshold value (normal brightness) to determine whetherthe brightness is low. If the brightness is low, the flow advances tostep S603; if not, the flow advances to step S604, and the CPU 151performs control such that the infrared reduction filter 106 is placedin the light path. In step S603, the CPU 151 performs control such thatthe infrared filter 106 moves away from the light path.

In step S605, the CPU 151 adds and reads out image signals from eachgroup of four photoelectric transducers of all photoelectric transducersforming the imaging device 141. The signal addition unit may also beincorporated into the imaging device 141. In this case, whether to readout an image signal from each photoelectric transducer or read out anadded image signal can be switched by a control signal from the CPU 151.Also, the CPU 151 sets the imaging signal processing unit 142 so as toread out image signals at a frame rate higher than a normal frame rate.

In step S606, the CPU 151 controls the imaging signal processing unit142 to sense a monochrome image at high sensitivity. In step S607, theCPU 151 causes a motion detection unit 152 to execute motion detectionby using the image signal acquired at high sensitivity. If no motion isdetected, the flow returns to step S601. If a motion is detected, theflow advances to step S609. In step S609, the CPU 151 causes a focuscontrol unit 135 to detect a focused focal point. In step S610, the CPU151 corrects the focused focal point for infrared recording and visiblelight recording.

In step S620, the CPU 151 places the infrared reduction filter 106 inthe light path in order to perform color recording. In step S621, theCPU 151 sets the imaging device 141 so as to read out image signals fromall the photoelectric transducers. Consequently, as shown in FIG. 5A,image signals for forming a color image can be acquired.

In step S622, the CPU 151 measures the brightness of the object from theimage signals. In step S623, the CPU 151 determines whether thebrightness of the object is low. If the brightness is not low, the flowadvances to step S625. If the brightness is low, the flow advances tostep S624, and the CPU 151 turns on a video light as a lighting device124.

In step S625, the CPU 151 starts recording a high-resolution colormoving image. In step S626, the CPU 151 temporarily stores data (movingimage data) of the taken color moving image in a RAM 154. In step S627,the CPU 151 reads out the moving image data from the RAM 154, andtransmits the readout moving image data to an external apparatus (e.g.,a file server) via a network interface 157.

In step S628, the CPU 151 detects the motion of the object by using themotion detection unit 152. In step S629, the CPU 151 determines whetherthe motion is detected by the motion detection unit 152. If the motionis detected, the flow returns to step S628 to continue moving imagerecording. If no motion is detected, the flow advances to step S630, andthe CPU 151 stops moving image transmission. In addition, in step S632,the CPU 151 turns off the video light. After that, the flow returns tostep S601. Note that it is also possible to record the moving image dataon the recording medium 156, instead of distributing it to the network.The image may also be displayed on the monitor via a video output unit158.

Note that FIG. 6 shows no step of executing autofocusing after thefocused focal point correction (S610) is executed, but it is of coursealso possible to continuously execute autofocusing. This is because thedistance to an object can successively change during moving imagerecording. In this case, the focus control unit 135 continuouslycontrols autofocusing even during moving image recording, by using thefocused focal point determined in step S610 as a start point.

In the first embodiment, still image recording using the imaging device141 having the primary color filters is explained. In the secondembodiment, moving image recording using the imaging device 141 havingthe complementary color filters is explained. However, these embodimentsare of course mere examples. For example, it is also possible to recordstill images by using the complementary color filters, or record movingimages by using the primary color filters.

The present invention can be applied to a system constituted by aplurality of devices, or to an apparatus comprising a single device.Furthermore, it goes without saying that the invention is applicable toa case where the object of the invention is attained by supplying aprogram to a system or apparatus.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadcast interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2005-228472 filed on Aug. 5, 2005, which is hereby incorporated byreference herein in its entirety.

1. An imaging apparatus comprising: an image taking unit which takes animage of an object; an infrared reduction filter formed in associationwith said image taking unit; a filter control unit which controls tomove said infrared reduction filter away from a light path associatedwith said image taking unit when a change relating to an object is to bedetected, and which controls to move said infrared reduction filter ontothe light path when an image of the object is to be recorded; adetecting unit which detects a change relating to an object on the basisof a plurality of images taken by said image taking unit; a recordingcontrol unit which records a color image of the object by enabling saidinfrared reduction filter by said filter control unit, when a changerelating to an object is detected; and a focal point detecting unitwhich detects a focused focal point of an imaging optical system byusing a hi-frequency component of signal components contained in animage signal output from said image taking unit, while said infraredreduction filter is moved away from the light path, wherein said imagetaking unit takes the image at a first frame rate when an image of theobject is to be recorded, and said image taking unit takes the image ata second frame rate higher than the first frame rate when a changerelating to an object is to be detected, wherein after said infraredreduction filter is moved onto the light path, said image taking unitkeeps the focused focal point detected while said infrared reductionfilter is moved onto the light path, and said recording control unitrecords a color image taken by said image taking unit in accordance withthe detected focused focal point detected by said focal point detectingunit.
 2. The apparatus according to claim 1, wherein when a changerelating to an object is to be detected, said image taking unit outputsimage signals smaller in number than all pixels forming in said imagetaking unit.
 3. The apparatus according to claim 2, wherein when achange relating to an object is to be detected, said image taking unitreads out only image signals from some of a plurality of pixels includedin said image taking unit.
 4. The apparatus according to claim 1,wherein said image taking unit takes the color image by using all pixelsin an imaging region of said image taking unit.
 5. The apparatusaccording to claim 1, further comprising a lighting unit which disableslighting when a change relating to an object is to be detected, andwhich enables lighting when the image is to be recorded.
 6. Theapparatus according to claim 1, further comprising a transmitting unitwhich transmits the recorded color image outside.